8224214: [AIX] Remove support for legacy xlc compiler

Reviewed-by: erikj, kbarrett, mdoerr, dholmes

src/hotspot/share/gc/shared/oopStorage.hpp

@@ -183,10 +183,7 @@ public:
   // private types by providing public typedefs for them.
   class TestAccess;
 
-  // xlC on AIX can't compile test_oopStorage.cpp with following private
-  // classes. C++03 introduced access for nested classes with DR45, but xlC
-  // version 12 rejects it.
-NOT_AIX( private: )
+private:
   class Block;                  // Fixed-size array of oops, plus bookkeeping.
   class ActiveArray;            // Array of Blocks, plus bookkeeping.
   class AllocationListEntry;    // Provides AllocationList links in a Block.
@@ -224,10 +221,7 @@ private:
   const char* _name;
   ActiveArray* _active_array;
   AllocationList _allocation_list;
-AIX_ONLY(public:)               // xlC 12 on AIX doesn't implement C++ DR45.
   Block* volatile _deferred_updates;
-AIX_ONLY(private:)
-
   Mutex* _allocation_mutex;
   Mutex* _active_mutex;
 
@@ -248,9 +242,7 @@ AIX_ONLY(private:)
   Block* find_block_or_null(const oop* ptr) const;
   void delete_empty_block(const Block& block);
   bool reduce_deferred_updates();
-AIX_ONLY(public:)               // xlC 12 on AIX doesn't implement C++ DR45.
   void record_needs_cleanup();
-AIX_ONLY(private:)
 
   // Managing _active_array.
   bool expand_active_array();